WO1996036748A1 - Metallic sheets treated with resin-chromate and reduced in leaching of chromium - Google Patents

Abstract

Metallic sheets treated with a resin-chromate, having an excellent corrosion resistance, particularly an excellent corrosion resistance when the treated coating is damaged by working or flawing, and being reduced in the leaching of chromium into an alkaline degreasing solution, a water-soluble rolling oil, dew condensation water, etc. One embodiment of the metallic sheets has thereon a resin-chromate coating composed mainly of a water-dispersible emulsion resin and a chromium compound, and is characterized in that the ratio of the average center face roughness Ra to the average protrusion distance P, Ra/P, as measured by observation of the outermost surface of the resin-chromate coating under an interatomic-force microscope is not more than 0.3 and that the ratio of the average protrusion distance P to the average height H of the resin-chromate coating, i.e., P/H, is 0.01 to 0.5.

Description

 Description Metal plate with hardly soluble resin chromate treated

 TECHNICAL FIELD The present invention relates to a chromated metal sheet, and particularly to a resin chromated metal sheet having excellent resistance to mouth opening. More specifically, in the present invention, the zinc-coated steel sheet, the aluminum-coated steel sheet, the zinc alloy sheet, the aluminum alloy sheet, and the corrosion resistance of the steel sheet, in particular, suffered from coating damage due to processing and scratching. The present invention relates to a resin chromate-treated metal plate that has excellent corrosion resistance at the time of application and has little chromium elution in alkaline degreasing solution, water-soluble rolling oil, dew condensation water and the like.

 Background art

 Chromate treatment has been conventionally known as a corrosion prevention treatment for zinc-based plated steel sheets, aluminum-based plated steel sheets, zinc alloy sheets, aluminum alloy sheets and steel sheets. Currently used chromate treatments are roughly divided into electrolytic chromate treatment and reactive chromate treatment mainly using trivalent chromium, and coating that contains hexavalent chromium and is dried without washing after coating. There is mold chromate treatment.

 Recently, chromate-treated metal sheets have been widely used for applications such as home appliances, building materials, and automobiles, and customers have come to demand various performances. For example, uniformity of appearance, fingerprint resistance, adhesion to paint, corrosion resistance of flat material in bare use, corrosion resistance in machined parts and scratched parts, and poorly soluble chromium in alkali degreasing.

Of these, the poor solubility of chromium is an issue that needs to be improved especially in the coating type chromate treatment that contains a large amount of hexavalent chromium, but since hexavalent chromium is an excellent anti-inhibitory agent, the coating type It is not easy to make the mouth hardly soluble without damaging the high corrosion resistance of the mouth mate. As a technique for hardly dissolving the chromium in the chromate film, for example, as disclosed in Japanese Patent Application Laid-Open No. 3-216683, heating for chromate formation is performed at a relatively low plate temperature of 300 ° C. How to do it at high temperatures is known. However, according to this method, hexavalent chromium is reduced by heating to form trivalent chromium during heating, and hexavalent chromium hardly remains in the inside. Significantly inferior to chromate males containing hexavalent chromium.

 Also, as can be seen in JP-A-4-158082 and JP-A-5-287584, reduction of a resin such as polyacrylic acid or alcohol in a chromate treatment bath. It is also known to add an agent, reduce and fix hexavalent chromium, and crosslink trivalent chromium in the resin. According to these methods, the corrosion resistance is improved due to the barrier effect of the resin. At sites where the chromate film is broken, such as in the machined part and the damaged part, self-healing action due to elution of hexavalent chromium does not work. Therefore, the problem of corrosion resistance still remains in the processed and scratched parts.

 Chromate-treated metal sheets In order to be widely used in the future, it is essential to make chromium hardly soluble.However, it has maintained the level of performance required so far, especially high corrosion resistance in the machined part and the ^ part. It has not been possible with the prior art to achieve this.

 An object of the present invention is to provide excellent corrosion resistance, particularly in areas where the treated film is damaged due to processing or scratching, and the elution capacity of hexavalent copper to alkaline degreasing solution, water-soluble rolling oil, water, etc. An object of the present invention is to provide a metal plate treated with resin chromate.

 Disclosure of the invention

In a mixture of an emulsion resin and an inorganic component such as a chromium compound, if the resin particles are fused and soluble hexavalent chromium is encapsulated in the network of resin particles, the dissolution output of hexavalent chromium is suppressed. However, only at the site where the force was damaged, elution of hexavalent octane occurs and the coating is repaired. In order to realize such advantages, it is necessary to set the physical conditions of resin chromate as follows.

 -Resin particles constituting the outermost surface of the film shall be fused to such an extent that hexavalent chromium is not easily eluted.

 Even in the bulk of one film, the volume balance between the resin phase and the chromium compound phase is kept within the specified range, and it is sufficient to suppress excessive elution of chromium (VI) valent chromium due to fusion of resin particles in the resin phase. Things.

 —Since the fusion state of the film is affected by the fine irregularities on the surface of the resin particles, which are factors that hinder fusion, controlling the fusion state in the bulk of the film can also be achieved by controlling such fine irregularities. can do.

 — Even if the volume balance of the resin phase and the chromium compound in the bulk of the coating is the same, it is better for the chromium compound to be unevenly distributed to some extent than to be uniformly dispersed in the coating. Since the total amount of hexavalent chromium encapsulated in the area increases, the self-healing function at the damaged part increases.

 In addition to the above-described physical conditions of the resin chromate film, suppression of the elution of hexavalent chromium can also be realized by controlling the chemical interaction between the chromium compound and the resin particle surface as follows.

 If the resin is made to contain the carbodiluid conjugate in such a manner that the eluted chromium can be trapped in a chelate manner, it is possible to achieve both the poor solubility of chromium and the corrosion resistance at the damaged part.

One resin contains a protonic or reducing functional group, and by utilizing the interaction between the functional group and the chromium compound, a part of the chromium compound is removed from the surface of the resin particles and Z or inside. If the structure is dispersed in the form of spots, favorable results can be obtained. The chromium-insoluble resin-chromate-treated metal plate according to the present invention has the following requirements A to F.

 A. The present invention relates to a metal plate on which a resin chromate film mainly composed of a water-dispersible emulsion resin and a chromium compound is formed, which is obtained by measuring the outermost surface of the resin chromate with an atomic force microscope. The ratio Ra ZP of the average convex part spacing P and the center plane average roughness Ra is 0.3 or less. Further, a ratio PZH of the average interval P of the convex portions to the average thickness H of the male resin chromate is 0.01 to 0.5.

 Hereinafter, the present invention will be described in detail.

 If the surface of the resin chromat film formed using the emulsion resin is set at the resolution of an atomic force microscope, periodic undulations caused by the emulsion resin particles can be detected. The average roughness R a of the center plane has a correlation with the roughness of the periodic undulations, and the average interval P of the projections has a correlation with the particle diameter of the emulsion resin used, and the ratio Ra as the fusion of the emulsion resin particles progresses. ZP is small, and if it is less than 0.3, both corrosion resistance and chromium insolubility are compatible.

 Further, by setting the ratio PZH of the above P and the above H in the range of 0.01 to 5, these characteristics are further improved.

 Atomic force microfiber is: 検 知 The sensing needle is moved relatively so as to keep the atomic force (often van der Waalska) acting between the atoms existing on the surface and the sensing needle constant, and the film surface Is to measure the unevenness of the surface. By examining the irregularities at the atomic level, extremely fine irregularity information can be obtained from a normal contact type surface roughness meter. Compared to the atomic level, the contact-type surface meter examines the average roughness, and cannot discuss the surface roughness depending on the fusion state of the resin particles. Becomes possible.

Center plane average roughness R a is the surface of the resin chromate film of 2 5 m ² area Prof The aisle was measured by atomic force microscopy, and was obtained by the following equation.

 1

Ra = S ^i] J ^Lx tf (x, y) I dxdy

LxLy ^{0. 0}

 In the equation, Lx and Ly represent the dimensions of the surface in the x and y directions, respectively, and f (x, y) represents the roughness surface with respect to the center plane (the volume created by this plane and the surface shape is equal above and below this plane). . Ra is dependent on the particle size of the resin used, and the force having a large value when the particle size is large becomes smaller as the fusion of the resin particles progresses.

 The average interval P of the convex portions is an average interval between the convex portions of the periodic surface undulation between any two points on the atomic force microscope image of the surface of the resin chromatized film. An example is shown in Figure 1. As shown in Fig. 1, a periodic surface undulation caused by resin particles is observed between any two points on the atomic force microscopic fiber image, and the distance between the protrusions is approximately

 0.125 m. The average interval P of the convex portions was calculated as the average interval between any two points and a total linear distance of 20 m. The average interval P of the convex portions, which is the interval between the undulations caused by the resin particles, varies depending on the fusion state, but has a positive correlation with the particle diameter.

 RaZP is a value that offsets the effect of particle size, and is an effective figure to grasp the progress of fusion. Ra / P decreases as the fusion of the emulsion resin particles progresses.

In the process of drying after the chromate treatment liquid is applied, the emulsion resin particles cause fusion with adjacent resin particles in the film, but if Ra / P is greater than 0.3, the emulsion resin particles Since the fusion of the resin particles is incomplete or hardly progressed and the network of the emulsion resin is not strong, hexavalent chromium in the film is easily eluted by contact with water or the like. If the RaZP value is 0.3 or less, the fusion of the resin particles progresses, and the hexavalent chromium in the film is surrounded by the resin particle network, and the poorly soluble chromium and the processed and scratched parts Corrosion resistance is compatible. Ra If the ratio is set to 0.1 or less, the resin particle network becomes stronger, and the chromium elution resistance can be exerted even in a severe environment where the resin particle comes into contact with alkali, boiling water, or the like.

 Furthermore, in order to improve the chromium hardly soluble property, the processed part, and the corrosion resistance, it is necessary to apply an emulsion resin having a particle diameter suitable for the thickness of the film and to control the fusion state of the resin particles. In other words, if the ratio of P, which has a correlation with the particle diameter, to the thickness H of the coating is greater than 0.5, the particle strength becomes too large relative to the thickness of the coating, and the denseness of the coating is impaired. Since the ratio of the existing pore force to the existing film becomes large, the elution of hexavalent chromium cannot be suppressed. Also, PZH

 If the value is smaller than 0.01, the contact area between the resin particles and the chromium compound increases, so that hexavalent chromium is easily reduced by the resin, and the self-corrosion prevention function becomes insufficient. Therefore, in a resin chromate-treated metal plate that is highly compatible with chromium insolubility and processed parts, and scratch resistance, the ratio PZH of the average distance P between the convex portions and the average thickness H of the resin chromate film is 0.01. It is preferable to suppress the force within the range of 0.5.

 Control within the above range makes it possible to enclose hexavalent chromium, which has a self-corrosion protection function, in the gaps between the resin particles, not only to suppress the elution of chromium, but also to damage the film due to processing and scratching. At the time, the hexavalent chromium encapsulated in the resin particles elutes only into the damaged part, and can exert its self-corrosion protection function.

 The average thickness H of the film can be selected as appropriate, and is usually about 0.1 #m to 5 m. If the average thickness of the film is less than 0.1 m, sufficient corrosion resistance cannot be secured, and if it is more than 5 / zm, the raw material cost and drying cost become low, which is economically undesirable.

The resin that can be used in the present invention is not particularly limited as long as it is a water-dispersible emulsion resin. For general use, for example, epoxy resin, polyurethane resin, acrylic resin, styrene / maleic acid resin, phenol resin, and polyolefin Examples include resins or copolymers or mixtures of two or more of these. Of these, in particular, acrylic trees It is suitable for a vinyl resin emulsion represented by a fat or the like. As the compound constituting the vinyl resin emulsion, a (meth) acrylic resin is preferable. For example, (meth) acrylic acid and its ester, a glycidinole group-modified (meth) acryl compound, and urethane resin ( Meth) Compounds obtained by copolymerizing one or two or more of acrylic compounds, aromatic vinyl compounds such as styrene, and polyolefins such as ethylene-butene can be used. The method of emulsifying the emulsion is not particularly limited, but is preferably a soap-free emulsion which does not use an emulsifier which can be a factor inhibiting fusion of the particles. Although the glass transition temperature of the resin is not particularly limited, for example, when the drying temperature of the metal plate is 50 to 60 ° C at the ultimate plate temperature, the range of the glass transition temperature of the resin is 140 to 2 About 0 ° C is good. If the glass transition temperature is too low, the abrasion resistance of the resin chromate is impaired, and if it is too high, the corrosion resistance after processing of the fiber is impaired.

 Examples of the chromium compound include chromic anhydride and reduced chromic acid obtained by partially reducing the same with starch or the like, or potassium dichromate, ammonium dichromate, sodium dichromate, potassium chromate, ammonium chromate, sodium chromate. It is possible to use a dichromate or a chromate such as the above. The content of the chromium compound in the resin chromate is preferably 5% to 80%. If it is less than 5%, the corrosion resistance is insufficient, and if it is more than 80%, the effect of suppressing the dissolution of the resin in the mouth cannot be sufficiently exhibited.

 In addition to the above, inorganic sols such as silica, alumina, and titania, inorganic acids such as phosphoric acid, polyphosphoric acid, and boric acid, and fluorides can be contained in the resin chromate treatment as needed.

The resin chromate-treated metal plate of the present invention is obtained by mixing the above water-dispersible emulsion resin, a chromium compound, and an inorganic compound such as phosphoric acid to form a resin chromate treatment bath, and applying this to the surface of the metal plate. It can be manufactured by drying. As a coating method, there is no particular limitation, and a roll coater, a ringer roll, a spray, a barco, a dipping, an air knife drawing and the like can be used. In addition, drying is not particularly limited as long as the film is heated to a temperature higher than the minimum curing temperature of the resin used.The film is heated to a temperature higher than the minimum film formation temperature by 1 ° C or more. Preferably.

 Metal sheets applicable in the present invention include zinc-plated steel sheet, zinc-nickel plated steel sheet, zinc-iron plated steel sheet, zinc-chrome plated steel sheet, zinc-aluminum plated steel sheet, zinc-titanium plated steel sheet, Zinc-magnesium coated steel sheet, zinc-manganese coated steel sheet, sub-forced electric plating, hot-dip plating, vapor-deposited steel sheet, aluminum or aluminum alloy-plated steel sheet, lead or lead alloy-plated steel sheet, tin or tin alloy Small amounts of dissimilar metal elements or impurities such as cobalt, molybdenum, tungsten, nickel, titanium, chromium, aluminum, manganese, iron, magnesium, lead, antimony, tin, copper, cadmium , Arsenic, etc., or silica, alumina, Includes those in which inorganic substances such as titanium are dispersed. Furthermore, for multi-layer plating in which two or more of the above platings are sequentially applied, or for multi-layer plating in which the above plating is combined with other types of plating, such as iron plating and iron-mono plating, etc. Is also applicable. Further, a zinc plate, a zinc alloy plate, an aluminum plate, an aluminum alloy plate, a steel plate, and the like can also be used.

B. The present invention provides a resin chromate film having an arbitrary cross section in which the area ratio of a resin phase separated by a chromium compound and a clear boundary is 40 to 95%, and It is characterized in that the area ratio is 20 to 100%. Hereinafter, the present invention will be described in detail.

Resin phase or fused resin particles, or area ratio of resin phase or resin particles in resin phase The area ratio of the fused body can be observed and analyzed by, for example, a transmission electron microscope image of a section of the resin chromate film of the present invention. Specifically, using an Ultra MIG mouth tome, an ultra-thin section with a thickness of 10 O nm or less was made on a metal plate treated with resin chromatography in the vertical or horizontal direction with respect to the treated surface, and this was taken with a ¾-type electron microscope. O Observation and analysis by o

 FIG. 2 shows a transmission electron micrograph of an ultrathin section of the resin chromate film of the present invention prepared in the horizontal direction with respect to the treated surface. In the transmission electron micrograph of FIG. 2, the chromium compound force << existing part force is suppressed to suppress the transmission of the electron beam, and a clear boundary is formed between the resin phase and the chromium compound phase.

 FIG. 3 shows a portion corresponding to the resin phase and the resin particle fused body defined in the present invention. The resin phase of the present invention is a portion where power is transmitted in FIG. 2 and a white portion in FIG. Here, the resin phase defined in the present invention includes the spotted chromium compound dragon having a diameter of 5 O nm or less, which is observed in FIG. The black part in Fig. 3 is chromium compound.

 Further, among the resin phases, the resin particle fused body in which two or more resin particles of emulsion resin are clearly judged from the shape and size to have been fused is considered.

 The area ratio of the resin phase of the present invention is an area ratio of the resin phase with respect to the total area (%), and the percentage of the resin particle fused body in the resin phase is the resin particle fused area with respect to the resin phase area. The area ratio (%) of the body. These can be calculated by tracing photographs as shown in Fig. 3 and measuring the area ratio of each, or by directly measuring photographs using commercially available image processing software. Each area ratio is an average value obtained by sampling at 10 or more locations.

The present inventors have studied the performance of a resin chromate-treated metal plate obtained by variously changing the mixing ratio of the resin and the chromium compound, the particle size of idiot or the glass transition temperature, the heating pattern during drying, and the transmission electron of the section. Structure of treated film obtained by microscopic observation The relationship with the above features was examined. As a result, when skin and structure were controlled by using the area ratio of the resin phase in the film and the area ratio of the resin particle fused material in the resin phase as guidelines, the hexavalent chromium in the resin chromate film formed a resin particle network. It was found that the structure was surrounded and the issues could be solved.

 In other words, a chromium compound containing hexavalent chromium is necessary to ensure the corrosion resistance of the processed and scratched parts. If the area ratio of the resin phase separated by more than 95%, the corrosion resistance of the welded part and the damaged part is remarkably impaired, and if it is less than 40%, the chromium compound is three-dimensionally formed by the fused resin particles. Chromium is difficult to enclose, making it difficult to secure the insolubility of chromium.

In addition, in the process of drying after the application of the chromate treatment liquid, the emulsion resin particles evaporate in the treatment liquid mainly composed of water or the like, and the resin particles approach each other in the interior. At this time, if the glass transition of the resin is too high relative to the drying, or if the drying is insufficient, the fusion of the resin particles in the coating is incomplete or hardly progresses, and the fused resin particles are hardly formed. Not generated. As described above, when the area ratio of the fused resin particles in the resin phase is less than 20%, three-dimensionally, most of the resin particles have a structure surrounded by a chromium compound phase containing hexavalent chromium. Hexavalent chromium in the film is easily eluted by contact with water. On the other hand, when the area ratio of the fused resin particles in the resin phase is 20% or more, the network of the emulsion resin is three-dimensionally formed, and the chromium compound containing hexavalent chromium is formed by the resin particles. The structure is surrounded, and chromium is hardly soluble. Therefore, in order to achieve both corrosion resistance and chromium resistance in the processed and scratched areas, the area ratio of the resin phase should be 40% i: 95% or less, and the area of the resin particle fused body in the resin phase The rate must be controlled to 20% J¾ ± 100% or less. It is more preferable that the average value of the size of the fused resin particles is equal to or more than 5 resin particles. The resin that can be used in the present invention is not particularly limited as long as it is a water-dispersible emulsion resin.Generally, for example, epoxy resin, polyurethane resin, acrylic resin, styrene maleic acid resin, phenol resin, Polyolefin tree

There are two or more copolymers and mixtures. Among these, a vinyl resin emulsion represented by an acrylic resin is particularly preferable. As the compound constituting the vinyl resin emulsion, (meth) acrylic resin is preferable. For example, (meth) acrylic acid and its ester, dalicidyl group-modified (meth) acryl compound, urethane-modified (meth) Compounds obtained by copolymerizing one or more of acrylic compounds, aromatic vinyl compounds such as styrene, and polyolefins such as ethylene and butadiene can be used. The method of dispersing the emulsion is not particularly limited, but a soap-free emulsion that does not use an emulsifier that can be a factor for inhibiting fusion of resin particles is more preferable. Although the glass transition temperature of the resin is not particularly limited, for example, when the drying temperature of the metal plate is 50 to 60 ° C at the ultimate plate temperature, the range of the glass transition temperature of the resin is 140 to 2 About 0 ° C is good. If the glass transition temperature is too low, the scratch resistance of the resin chromate film is impaired, and if it is too high, the film forming property and the corrosion resistance after processing are impaired.

C. In the present invention, the resin chromium skin is cut in a horizontal direction with respect to the treated metal surface, the emulsion particles are missing on an arbitrary cut surface, and the chromium pool containing the chromium compound is reduced in area ratio. It is characterized by having 5 to 60%. Also, the distribution concentration of the chromium pool is 10 or more per 5 mx 5 m.

 Hereinafter, the present invention will be described in detail.

Means for Solving the Problems The inventors of the present invention have proposed that while forming a continuous film surrounding resin particles mainly with hardly soluble trivalent chromium, a small amount of a chromic acid conjugate containing a larger amount of soluble hexavalent chromium can be obtained by resin chromatography. To make it coexist in G, the method is sharp: ^ As a result, the emulsion particles are controlled by controlling the method of stabilizing the emulsion, the type and M of the functional group of the emulsion resin particles, the presence state of the chromate compound in the treatment bath, and the drying conditions of the resin chromate. It has been found that the chromium pool containing the missing chromic acid compound can be dispersed in the resin chromate ^ at various area ratios and densities.

 Fig. 4 shows a transmission electron micrograph of the cut surface of such a resin chromate film, and Fig. 6 shows a schematic diagram of the cross-sectional structure. Reference numeral 1 denotes emulsion resin particles, 2 denotes a chromium reservoir, and 3 denotes a metal plate. Examination of the performance of the resin chromate-treated metal plate produced in this way revealed that, as expected, a reduction in the chromium elution amount and a high degree of compatibility between the processed part and the scratch resistance were achieved.

 In the present invention, the chromium pool is dispersed in the resin chromate film. It is sufficient that the depth of the chromium reservoir is not less than the particle diameter of the emulsion resin particles. In addition, the missing portion of the emulsion particles forming the chromium pool does not need to penetrate through ^, and the emulsion particles may exist in the upper part and / or the lower part thereof. The size of the chromium pool must be at least 5 emulsion resin particles. If it is smaller than this, hexavalent chromium is reduced by contact of the chromium compound and the resin particles, and hexavalent chromium inside the chrome pool is strongly reduced, which is not preferable. Usually, the size is about 10 to 30 resin particles, and the length is around 1 micron. The larger the amount of chrome pool, the more advantageous the corrosion resistance of the machined and scratched parts. Chrom pool on any cut surface when the resin chromate film is cut in the horizontal direction to the treated surface If the area ratio exceeds 60%, the secondary adhesion of the paint will be impaired. On the other hand, if the area ratio is less than 5%, the effect on the corrosion resistance of the processed and scratched parts is not significant.

In addition, the higher the density of the chrome pool, the longer the self-healing function in the machined part and the damaged part. Percentage of chromium pool at any cut surface is in the range of 5 to 60% For this reason, it is strongly desirable that the distribution density is 5 111 5 5 111 ぁ or more than 10 points.

 Although ^^; ^ of the chromium pool is not clear, it is considered that the main causes are the pseudo-aggregation of emulsion resin particles in the resin chromate bath and the evaporation of water during the drying process. For example, if the emulsion is stabilized by a low-molecular weight surfactant, it is difficult to form a chromium pool in “^. This is considered to be a cause of contact hindrance, and it is difficult for pseudo-aggregation of the resin particles to occur.

 On the other hand, in a so-called soap-free emulsion that does not use a low amount of surfactant, chromium accumulation is more likely to occur. The soap free emulsion has a relatively small resistance to contact inhibition between resin particles, and it is considered that the emulsion resin particles are in a state of pseudo-aggregation in the bath, that is, tens of particles are gathered and loosely bound. When this is applied to the metal, the resin particles will not be arranged uniformly, but will be in a clustered arrangement per pseudo-agglomeration unit. In the gaps between these pseudo-agglomeration units, the evaporation rate of water in the ^ process is faster than that of the surroundings, and the flow of resin particles to that part is hindered. On the other hand, it is presumed that the chromic acid conjugate having a low viscosity flows into this, and as a result, a chromium accumulation force with missing resin particles is generated.

 It is estimated that the content of soluble hexavalent chromium in the chromic acid conjugate in the chromium pool is higher than the content of hexavalent chromium in the continuous film of the chromic acid conjugate that surrounds the emulsion resin particles. Is done. The reason is that, in a continuous film, the contact area with the reducing resin is large, and the reduction of the chromic acid compound gradually progresses even after coating and drying, whereas the resin in the chromium pool This is because the contact force is low and the reduction is suppressed.

The area ratio and distribution density of the chromium reservoir vary depending on the type and concentration of the emulsion resin particles, the state of the presence of the chromate compound in the resin chromate bath, and the drying conditions of the resin chromate male. Presence of chromate compounds in baths. The presence state is the type and amount of ions coordinating around chromium and the association state of the chromium complex, which changes depending on the coexisting ions in the treatment bath. Among the factors governing the formation of chromium pools as described above, the type and concentration of the functional group of the resin, the state of the presence of the chromic acid compound in the bath, the size of the pseudo-aggregates of the resin particles in the bath, and the strength of the aggregation It seems to determine the.

 The resin that can be used in the present invention is not particularly limited as long as it is a water-dispersible emulsion resin, but in general, for example, epoxy resin, polyurethane resin, acrylic resin, styrene maleic resin, phenol resin, polyolefin Examples include resins or copolymers or mixtures of two or more of these. Among these, a vinyl resin emulsion represented by an acrylic resin is particularly preferable. As the compound constituting the vinyl resin emulsion, (meth) acrylic resin is preferable. For example, (meth) acrylic acid and its ester, glycidyl group ^ (meth) acryl compound, urethane modified (meth) Compounds obtained by copolymerizing one or more of acrylic compounds, aromatic vinyl compounds such as styrene, and polyolefins such as ethylene and butadiene are usable. The emulsion tfc ^ method is not particularly limited, but a soap-free emulsion which does not use an emulsifier which can be a factor for inhibiting fusion of resin particles is more preferable. Although the glass transition temperature of the resin is not particularly limited, for example, when the drying temperature of the metal plate is 50 to 60 ° C at the ultimate plate temperature, the range of the glass transition of the resin is 140 to 20 ° C. ° C is good. If the glass transition temperature is too low, the scratch resistance of the resin chromate is impaired, and if it is too high, the film formability and the corrosion resistance after processing are impaired. The size of the resin emulsion particles is a force that can be selected as appropriate. Usually, particles having a particle size in the range of 0.5 to 0.5 m are used.

Next, the relationship between the presence state of the chromic acid conjugate in the bath and the pseudo-aggregation of the resin emulsion will be described. The chromate compound itself aggregates under certain conditions. Generally, such agglomeration is called gelation, and resin particles are also contained in a network of chromate compounds. Incorporation, forming a much stronger aggregate than the pseudo-aggregation of resin particles. Therefore, in order to pseudo-aggregate the resin particles, it is necessary to select conditions under which the coagulation force of the chromate compound itself does not occur.

Examples of the chromic acid conjugate that can be used in the present invention include chromic anhydride and reduced chromic acid obtained by partially reducing the chromic anhydride with starch, or potassium dichromate, ammonium bichromate, sodium bichromate, chromium There are dichromates and chromates such as potassium citrate, ammonium chromate and sodium chromate. Of these, it is preferable to use chromic anhydride or reduced chromic acid obtained by partially reducing chromic anhydride from the viewpoints of bath stability, film forming properties, and economic efficiency. In order to prevent the chromic acid compound from condensing in the bath, it is effective to add an acid such as phosphoric acid, boric acid, sulfuric acid or nitric acid. In particular, phosphoric acid is the most effective. The amount of addition is not particularly specified, but in order to ensure bath stability under conditions where the bath temperature is higher than room temperature and is maintained for a long time, the chromic acid concentration in the bath (C It is advantageous to add at least 1.2 times more phosphoric acid (H ₃ PO ^ equivalent) than r〇 ₃

 —However, the drying conditions determine the final distribution density of the chromium pool. In general, the higher the evaporation rate of water by short-time drying in a high-temperature atmosphere, the higher the distribution density of the chromium pool tends to be. The drying temperature can be selected as appropriate according to the drying method and the integrity of the emulsion resin particles.If high-speed processing in a continuous line requires a short drying time of about 3 to 15 seconds, Temperature of 50 ° C or more is required. On the other hand, in order to prevent the chromic acid conjugated substance coexisting in the resin chromate film from being excessively reduced, it is strongly preferable to set the sheet temperature to 180 ° C. or less. Therefore, the range of the heating rate under this condition is approximately 2 to 50 ° CZ sec.

In the chromate treatment bath and film, besides resin emulsion and chromic acid compound, if necessary, inorganic sol such as silica, alumina, titania, zirconia, etc. Fluoride and the like can be contained.

 The thickness of the resin chromate film specified in the present invention is a force that can be selected as appropriate. Usually, the thickness may be about 0.1 to 5 cm. If it is less than 0.1, the effect as a continuous film cannot be obtained, and if it is 5; zm or more, it is not economical.

 Methods for chromate treatment on metal plates include coating by mouth and mouth, coating with ringer by mouth, dipping and air knife squeezing, coating by Barco and spraying, etc. It is possible to use it. In addition, the treatment can be carried out by one-stage treatment with a treatment bath in which a resin emulsion is mixed with a chromic acid compound and other additives, and by drying once.

 In order to observe the fine structure of the resin chromate film, the thickness of the resin chromate-treated metal plate after coating and drying was cut to 50 to 50 mm by cutting the metal plate horizontally with respect to the treated surface using an ultramicrotome. Sections of the 20 O nm key were prepared and analyzed with a transmission electron microscope.

 Fig. 4 is an example of observation of a resin chromate film formed by this method. It is observed that the arrangement of the resin emulsion particles is not uniform, and there are missing parts of several meters in size. FIG. 5 shows a portion of the chrome pool defined by the present invention. The presence of chromium compounds in the chromium reservoir at a high concentration suppresses the transmission of electrons, and is observed as dark areas in transmission electron micrographs. Therefore, in order to measure the area ratio of the chromium accumulation, a method of calculating the area ratio of a dark portion by performing binary image processing on a transmission electron microscope photograph is effective. The area ratio and distribution density of the chromium pool were determined by using a photo as shown in Fig. 4 and measuring at least 10 sites over an area of 5 m x 5 m or more.

D. The present invention relates to an image obtained by subjecting a surface unevenness distribution of a resin chromat film to a high-pass filter processing at a wavelength of 50 nm by a two-dimensional element Fourier transform to obtain a 0.5 nm It is characterized in that the area ratio of the convex portion showing the above displacement is 20% or less. Hereinafter, the present invention will be described in detail.

 The present inventors measured the unevenness distribution on the surface by atomic force microscopy in order to determine the existence density of the particles formed on the resin particle surface. In addition, we performed a high-pass filter process to remove wavelength components of 50 nm or more by two-dimensional Fourier transform of the measured values, and succeeded in finding the distribution of Puta particles of 50 nm or less. Figure 7 shows the unevenness distribution of the resin chromate metal plate obtained by the atomic force microscope. Fig. 8 shows an image of Fig. 7 after high-pass filter processing at a wavelength of 5 Onm.

 The present inventors have studied the relationship between the performance of a resin chromate-treated metal plate obtained by variously changing the resin composition and the internal structure of a film obtained by transmission electron microscopy and the surface structure measured by atomic force microscopy. As a result, the surface unevenness distribution of the resin chromate film measured by atomic force microscopy was determined to be 0.1% in the image that was subjected to a high-pass filter processing at a wavelength of 50 nm by two-dimensional Fourier transform. If the area ratio of the protrusions showing a displacement of 5 nm or more is more than 20%, the resin particles in the film will have a structure surrounded by a chromium compound. In addition, it was found that the chromium compound had an ability to elute from the film. This is because, in the process of drying after the chromate treatment liquid is applied, the process liquid mainly composed of water etc. evaporates and the resin particles come into close contact with each other in the male. This is probably because the fusion of the resin particles is hindered by the fine projections on the surface, and the resin cannot surround the epoxy compound.

On the other hand, when the area ratio of the convex portions showing a displacement of 0.5 nm or more in the image subjected to the above-mentioned noise pass filter processing is 20% or less, the resin particles come into direct contact with each other in the drying process. As a result, the resin particles are fused to form a three-dimensional network of the resin, which can surround the chromium compound. With such a structure, In addition to being able to suppress chromium elution at a high level, encapsulating hexavalent chromium, which has a self-corrosion protection food, in the resin particle gap, became a power source, and was damaged by processing and scratching Only at that time, it can be eluted into the hexavalent chromium force-damaged part enclosed in the resin particle gap and exert its self-corrosion protection function.

 The resin that can be used in the present invention is not particularly limited as long as it is a water-dispersible emulsion resin. For general use, for example, epoxy resin, polyurethane resin, acrylic resin, styrene maleic resin, phenol resin, polyolefin Examples include resins or copolymers or mixtures of two or more of these. Among these, a vinyl resin emulsion represented by an acrylic resin is particularly preferable. As the compound constituting the vinyl resin emulsion, a (meth) acrylic resin is preferable. For example, (meth) acrylic acid and its ester, glycidyl group ^ (meth) acryl compound, urethane modified (meth) Compounds obtained by copolymerizing one or more of acrylic compounds, aromatic vinyl compounds such as styrene, and polyolefins such as ethylene and butadiene can be used strongly. The method of emulsifying the emulsion is not particularly limited, but is preferably a soap-free emulsion which does not use an emulsifier which can be a factor inhibiting fusion of the resin particles. Although the glass transition of the resin is not particularly limited, for example, when the drying temperature of the metal plate is 50 to 60 ° C at the ultimate plate temperature, the range of the glass transition temperature of the resin is —40 to About 20 ° C is good. If the glass transition temperature is too low, the scratch resistance of the resin chromate is impaired, and if the glass transition temperature is too high, the film formability and the corrosion resistance after processing are impaired.

Examples of the chromium compound include chromic anhydride and reduced chromic acid obtained by partially reducing the same with starch or the like, or potassium dichromate, ammonium dichromate, sodium dichromate, potassium chromate, ammonium chromate, sodium chromate. It is also possible to use a dichromate or a cuprate, for example. The content of the chromium compound in the resin chromate female is preferably 5% to 80%. Less than 5% The erosion is insufficient, and if it exceeds 80%, the chromium compound inhibits fusion of the resin particles and the chromium elution of the resin is not sufficiently exerted.

 In addition to the above, inorganic sols such as silica, alumina and titania, inorganic acids such as phosphoric acid, polyphosphoric acid and boric acid, fluorides and the like can be contained in the resin chromate treatment film as required.

E. According to the present invention, when the resin chromate film is subjected to infrared absorption analysis after being immersed in boiling water, one or more infrared rays are detected within a range of 1670 to 1760 cm- ^{1 and} a range of 1500 to 1660 cm- ^1. It is characterized by having an absorption peak. Further, the specific power is high due to the absorbance of the maximum infrared absorption peak within the range of 1670 to 1760 cm- ^{1 and} the range of 1500 to 1660 cm- ¹ . High wavelength region peak: low wavelength region peak = 1: 0 1-1: 1 is characterized by being.

 Hereinafter, the present invention will be described in detail.

 In order to provide a chromate-treated metal plate having a small amount of chromium elution and having a self-healing function, the present inventors have made it possible to bond chromium ions with functional groups of certain carbonyl compounds in a clean and loose manner. It was considered effective to keep the film as it was in the chromate film. Therefore, steel sheets and aluminum sheets are treated in various processes in a chromate treatment bath containing a resin containing various carboninoleic compounds and a chromic acid compound as main components. As a result of examining the relationship with the ± characteristics, the problem is solved by controlling the strength of the bond between the chromium ion and the carbonyl compound to an appropriate range at the peak position in the infrared absorption spectrum. I found something.

In other words, the infrared absorption peak derived from the free carbonyl compound appears in the range of 1670 to 1760 cm- ¹ , whereas the infrared absorption peak of the carbonyl compound which seems to be bonded to the chromium ion in a clean manner is obtained. Infrared absorption peaks appear in the lower wavenumber range. Processed portion of the chromium elution those suppressed in the force 1 5 0 less than 0 c nT ¹ considered strong enough wavenumber is low chelate binding to degreasing solution or a water-soluble rolling oil, corrosion resistance in the wound is not On the other hand, if it exceeds 166 cm- ¹ , chromium elution is not sufficiently suppressed. When the infrared absorption peak is present in 1 5 0 0 cm-il 6 6 0 c π ¹ range, the processing unit and chromium sparingly soluble, scratches portion corrosion resistance highly compatible. Each infrared absorption peak may appear as a sharp single peak, or may appear as a plurality of adjacent peaks corresponding to a plurality of subtly different bonding states. The intensity ratio between the peak derived from the carbonyl compound and the peak believed to be due to chelating binding also affects the film performance.

 That is, when quantitatively comparing ¾ ^ based on the absorbance of the maximum absorption peak among the peaks derived from the ketoluponyl compound with the absorbance of the maximum absorption peak among the peaks considered to be due to chelating binding, chromium elution was observed. The effect of reducing the amount is greater as the relative strength of the chelating bond is higher, while the lower the relative strength of the chelating bond, the better the paint adhesion. A preferred range in which the two are balanced is 1: 0.1 to 1: 1.

 The strength of the chelating bond between the carbonyl compound and the chromium ion and the degree of progress of the reaction depend on the type of carbonyl compound used, the temperature of the treatment bath, the type of co-added ions in the treatment bath, and the heating during drying. C. In the evening, it can be controlled by post-treatment of the treated film after drying. The chelate bond is a force that is formed by a broadly defined acid-base interaction, the strength of the base (electron ^^ body) in the chelate bond depends on the type of carbonyl compound, and the bond depends on the state of chromium in the bath. Determines the strength of the acid (electron acceptor) at the surface, and the combination of the two determines the strength of the bond itself.

The acidity of the kokumitsui-dani mixture in the bath depends on the type of ions coordinating around the chromium ion and the state of association of the chromium ion, and the main factor controlling this is the treatment bath. And the type and amount of co-added ions in the treatment bath. In order to make the acid-base interaction with the resin containing the carbonyl compound according to the present invention suitable, it is effective to set the coexisting ions in the bath and the length of the bath as follows, for example. I understood that.

 That is, in an aqueous solution in which the concentration of hexavalent chromium in the bath was 10 to 200 g / l, 0.1 to 5% of sulfuric acid, and 0.1 to 5% After the addition of fluoride ions at a concentration of, the mixture is stirred at a bath temperature of 35 ° C or more and 70 ° C or less for 24 hours or more. After the temperature is returned to normal temperature, an inorganic additive such as silica or phosphoric acid is added as required, and then a predetermined amount of resin is added to form a chromate treatment bath. If the concentration of hexavalent chromium is less than 10 gZ1, the reaction is too dilute and the reaction is not efficient, and if it exceeds 200 gZl, the chromic acid aqueous solution becomes unstable and becomes easily gelled. If the sulfuric acid content is less than 0.1% based on the concentration of hexavalent chromium, a chelating reaction with the carbonyl compound-containing resin does not occur, and if it exceeds 5%, the reaction proceeds too much. Fluoride ion contributes to the stability of the chromium ion coordinated with chromium ion in the bath, and has no effect when the concentration of fluoride ion is less than 0.1% with respect to the concentration of hexavalent chromium. If it exceeds, it saturates. If the bath temperature at the time of stirring is lower than 35 ° C, the chromium ions in the film are not sufficiently activated by the post-treatment, so that the chelating reaction with the resin does not proceed sufficiently: ^ 1 and the temperature is reduced to 70 ° C. If it exceeds, the added sulfuric acid etc. will be concentrated because the evaporating rate of the permanent will be fast. If the stirring time is less than 24 hours, a sufficient chelating reaction with the resin does not occur. Immediately after stirring, if the mixture is not returned to room temperature and immediately mixed with the resin, a chelating reaction will occur violently, making it difficult to control.

The degree of progress of the chelating reaction can also be controlled by post-treatment after drying. As a post-treatment after drying for controlling the degree of reaction progress, immersion treatment with warm water or boiling water is effective. This is performed when the chelation reaction is not sufficient with only the steps up to coating and drying.Hexavalent chromium is activated in the coating by warm or boiling water. To cause a chelating reaction with the carbonyl compound, which is loosely fixed. This can be confirmed by measuring the infrared absorption spectrum before and after the immersion in boiling water. Both FIG. 9 and FIG. 10 show the infrared absorption spectrum of a resin chromate-treated film having a peak derived from the Carbo-Niroui compound at 173 cm- ¹ . There is no peak change due to boiling water immersion. In contrast, in the example of Fig. 10, a new peak is generated at ¹⁵⁹ cm ^_1 in addition to the original carbonyl peak by boiling water immersion. Examining the performance of these coatings, in the example of Fig. 9, no chelating reaction occurred at all, and chromium elution was not suppressed. On the other hand, FIG. 10 shows an example of the present invention, in which the chromium melting output is suppressed, and a high strength, a highly processed portion, a scratched portion, corrosion resistance, and paint adhesion are obtained.

The present invention is characterized in that it may be finally completed by post-treatment after coating and drying as described above. As the post-treatment, as described above, the most effective force is the immersion treatment in boiling water or hot water.In addition, long-term cold water immersion treatment, condensation due to long-term storage in a high-temperature, high-humidity environment, etc. Has been strongly confirmed to perform a similar function. Also, in some cases, the corrosive environment itself, such as salt spray, may perform post-treatment functions and promote chelating reactions. Therefore, the infrared absorption peak power of the resin chromate film as it is applied and dried <both boiling water immersion treatment, warm water immersion treatment, and cold water immersion treatment even for a chromate-treated metal plate that does not exist within the scope of the present invention. Certain of the present invention include all those which fall within the range of the present invention due to the infrared absorption peak power of the resin chromate due to high temperature or the like. The infrared absorption peak of the resin chromate film does not exist within the scope of the present invention when coated and dried. The quickest and most reliable method for determining whether a chromate-treated metal plate can be made the present invention by post-treatment is boiling. This is a water immersion treatment. That is, by immersing in boiling water for 30 minutes, the infrared absorption peaks of the resin chromate film that appear within the scope of the invention are all inventions, and those that do not are after any other method. The infrared absorption peak of the resin mate does not appear within the scope of the present invention even by the treatment, and is not the present invention.

 Examples of the carbonyl compounds usable in the present invention include β-diketones, 2-hydroxybenzaldehydes, 2-acylphenols, troborones, .3 hydroxy-14 pyrones, and carboxylic acids, esters and amides. And carboxylic acid derivatives. Carboxylic acid derivatives include, for example, acrylic acid, methacrylic acid, maleic acid, itaconic acid, acrylates, methacrylates, or copolymers of these or with styrene, acrylonitrile, vinyl acetate, etc. and so on. Two or more of the above may be used in combination. The content of these carbonyl compounds in the chromate film is preferably 1 to 60% by weight. If it is less than 1%, the effect of suppressing chromium elution is not sufficient, and if it exceeds 60%, the resin containing the carbonitrile compound becomes brittle and the film formability of the resin chromate is inferior.

 Examples of the type of resin containing these carbonyl compounds include epoxy resins, acrylic resins, polyurethane resins, styrene / maleic acid resins, phenol resins, polyolefin resins, and mixtures or copolymers of two or more of these resins. <Can be used. In addition, as for the method of containing, it is desirable to use chemical bonding by copolymerization or the like, but the effect can be exerted even by simple mixing. The form of the resin containing the carbonyl compound is not particularly limited as long as it is water-dispersible (emulsion). However, when compared with the ease of control of the chelating bond, no emulsifier is used. Particularly, a soap-free emulsion having a structure in which a hydrophobic resin core is surrounded by a hydrophilic substance containing a carbonyl compound, that is, a so-called core-shell structure is preferable.

F. The present invention relates to a chromium compound in which a chromium compound is dispersed in the form of spots on the emulsion resin particle surface and in the interior of the emulsion resin particles. The characteristic feature is that the average area ratio of the emulsion particles to the resin particles is 5 to 80% as an average value at an arbitrary cut surface of the emulsion particles. Further, in any cut surface of the emulsion resin particles, the dispersed compound has a dispersed density force of not less than 20 per 100 nm × 100 nm of the dispersed spot compound. Hereinafter, the present invention will be described in detail.

 The present inventors studied the interaction between the chromate compound and the surface or internal components of the resin particles, and dispersed the chromate compound on the surface of the resin emulsion particles and / or inside the resin emulsion particles, Two types of fine-grained chromic acid compound, which surround the resin particles, and a coumic acid compound dispersed on the surface of the idiot particles or / and inside the resin particles, coexist in the film. investigated. As a result, by controlling the emulsion stabilization method, the type and concentration of the functional groups of the emulsion resin particles, the state of presence of the chromic acid conjugate in the treatment bath, and the drying conditions of the resin chromate film, It has been found that the chromate compound can be dispersed in the form of spots on the surface of resin particles or inside Z and resin emulsion particles at various densities and area ratios.

 Figure 2 shows an example. By examining the performance of the resin chromate-treated metal sheet prepared in this way, it was found that, as initially expected, a reduction in the amount of chromium elution and a high degree of compatibility between the corrosion resistance of the processed and scratched parts were achieved.

In the present invention, the cupric acid compound is dispersed in the form of spots on the surface of the resin emulsion particles or inside the Z and resin emulsion particles. The greater the amount of the dispersed chromic acid conjugate, the more advantageous in the corrosion resistance of the processed part and the flawed part, but the area ratio of the resin emulsion particles to the resin emulsion particles is 8 as an average value at an arbitrary cut surface of the resin particles. If it exceeds 0%, the fusion between the resin particles is inhibited, and the mechanical properties of the resin chromate film, for example, the workability are deteriorated. On the other hand, if the average area ratio is less than 5%, the effect on the corrosion resistance of the processed and scratched parts is not significant. It is presumed that the chromic acid conjugate compound dispersed in the resin particles has a kind of fine domain structure and is dispersed on the surface or Z and inside of the resin. The physical and chemical properties of these microdomains also have a significant effect on the properties of the coating. For example, even if the average area ratio of the dispersed chromic acid compound is the same, the higher the density and the smaller the size of the spots (micro domains), the stronger the strength, and the lower the density and the larger the size of the spots. As a result, the self-healing function is maintained for a long time by dissolving the debris in the processed part and the wound part. Therefore, when the average area ratio is in the range of 5 to 80%, the number of spots of the dispersed chromic acid conjugate is 100 nm × 100 nm as an average value on an arbitrary cut surface of the resin particles. It is desirable that the number is 20 or more.

 The content and density of the chromic acid conjugate in the resin emulsion particles are determined by the method for stabilizing the emulsion, the type and view of the functional groups of the emulsion resin particles, the state of the chromate compound in the treatment bath, and the resin chromate film. It can be changed by controlling the drying conditions and the like. If the emulsion is stabilized by a surfactant, the dispersion of the chromic acid compound in the resin particles is unlikely to occur. On the other hand, in soap-free emulsions that do not use surfactants, there is no such contact inhibition factor, and the dispersion of the chromic acid compound contains resin particles. Type of government fiber ί Occurs depending on density Dispersion of chromic acid compound in resin particles and formation of microdomains are considered to be due to electrostatic interaction in a broad sense Force Functional groups contained in resin particles are electronic »sites It seems that the chromate compound acts as an electron acceptor.

At this time, it is considered that the interaction between the two and the resulting domain-like dispersion of the chromic acid conjugate in the resin particles are governed by the electrostatic interaction force field. In other words, it is greatly affected by the dielectric constant of the medium, the existence state of chromium ions and counter ions, and the effective charge density of the ionic substance, resin particle surface and inside. Especially chromic acid The state of presence of chromium in the treatment bath is important, and depends on the a¾ of the ion coordinated around chromium and the association state of the chromium complex.The main factors controlling this are Quantity.

 The area ratio and dispersion form (size, etc.) of the dispersed chromic acid compound are also affected by the heating pattern in the drying step after application of the resin chromate composition. This is thought to be due to the kinetics of the resin emulsion particles forming a film by mutual diffusion and fusion during the drying process. The water present between the resin particles induces a capillary force during the evaporation process, and the degree of fusion is determined by the balance between this force and the mobility of the resin particles. The mobility of resin particles is generally described as a function of the particle size and elastic modulus of the resin particles.In the case of a composite film containing a chromic compound, the chromic compound is applied to the surface and inside of the resin particles. Diffusion occurs at the same time, which complicates the process. The composition of the finally formed film is considered to be affected by the temperature (mm) and evaporation rate. In particular, the amount of the chromic acid compound dispersed in the resin particles is affected by the evaporation rate of water during drying. It is thought that the amount of the oxide of kumumu becomes lower.

One of the techniques suitable for observing the fine structure of the resin chromate film composed of the resin emulsion particles and the chromic acid compound is resin chromate treatment after coating and drying. In this method, a section with a thickness of about 100 to 200 11111 is created by cutting in the horizontal or horizontal direction, and this section is analyzed with a transmission electron microscope. Fig. 2 shows an example of observation of a resin chromate film formed by cutting in the horizontal direction with respect to the treated surface. A continuous film containing a finely granular chromic acid conjugate (b) surrounding the resin emulsion particles (a) and a chromic acid conjugate (c) dispersed on the surface of the resin particles or Z and inside the resin particles; Are clearly observed. The average area ratio and average density of the chromic acid compound dispersed on the surface of the resin particles and / or inside the resin particles at an arbitrary cut surface of the resin mouthmate are shown in the photograph. Was determined by actually measuring at least 10 resin emulsion particles.

The functional groups that interact with the chromic acid compound on the surface and inside of the resin emulsion particles include those chemically bonded to the chromic acid conjugate and those added chemically in the bath. Examples of the former one COOHヽhaving protic _{- S 0 3 H, - PO} (OH) 2 or the like, ¾ the latter [] water degradable, Ekisan resistance of the ester group, amino de group, Examples thereof include an alcohol amide group, an alcoholic hydroxyl group, and a daricidyl group. Two or more of these can be used in combination.

 As the type of resin, epoxy resin, acrylic resin, polyurethane resin, styrene / maleic acid resin, phenol resin, polyolefin resin, or a mixture of two or more of these resins and copolymers with other resins can be used. is there. The form of emulsion is powerful depending on the combination with the functional group, and can be used by emulsifying and polymerizing with a low amount of surfactant or by non-emulsion polymerization without using surfactant It is possible. The latter in which the functional group contained in the resin particles easily contacts the chromic acid conjugate is more desirable.

 BRIEF DESCRIPTION OF THE FIGURES

 Fig. 1 is a diagram showing the change in surface irregularities of the resin chromate-treated film surface as measured with interatomic fiber.

 FIG. 2 is a transmission electron micrograph of an ultra-thin section of the resin chromate film of the present invention prepared in a horizontal direction with respect to the treated surface, wherein (a) resin emulsion particles, (b) fine granular chromate compound, and (C) A chromic acid conjugate.

 FIG. 3 is a diagram schematically showing a portion corresponding to a resin phase and a resin particle fused body in FIG.

FIG. 4 is a transmission electron microscopic fiber photograph of a cut surface of the resin chromate film. FIG. 5 is a diagram illustrating a chromium pool.

 FIG. 6 is a schematic diagram showing a cross-sectional structure of a resin chromate film.

 FIG. 7 is a schematic diagram showing the unevenness distribution of the resin chromate metal plate obtained by the atomic force microscope.

 FIG. 8 is a schematic diagram showing an image obtained by performing one process of a high-pass filter with a wavelength of 50 nm on FIG.

 FIG. 9 is a diagram showing an infrared absorption spectrum of a resin chromatized film. FIG. 10 is an example of the present invention, in which a new peak is observed in the infrared absorption spectrum of the resin chromatized film.

 FIG. 11 is a graph showing the relationship between the area ratio of the dispersed chromic acid compound in the resin particles and the incidence of white spots in the processed part.

 FIG. 12 is a graph showing the relationship between the area ratio of the dispersed chromic acid compound to the resin particles and the chromium elution rate.

 FIG. 13 is a graph showing the relationship between the density of the dispersed chromic acid compound in the resin particles and the whitening rate of the processed portion.

 Example

 Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples.

Difficult case 1

 1. Types of metal plate

 The following metal plates were used for the resin chromate treatment.

GI: Hot-dip 14% lead-plated steel sheet (adhesion adhesion amount 90 g / m ² )

EG ： Electric m¾ lead plated steel plate (plated «20 g / m ² )

Zn-A 1: hot dip aluminum coated steel sheet (coating weight 120 g / m ^2, plating composition A lZZn-5/95)

2. Resin chromate treatment bath (1) Types of chromic acid

 Chromic anhydride partially reduced by starch was used.

 (2) Type of resin

 Particle size 0.04, 0.10, 0.15, 0.17, 0.30, 0.45,

 An acryl-based soap free emulsion having a glass transition temperature of 0.70 m and a glass transition temperature of 10 ° C was used.

 (3) Other additives

 Phosphoric acid (P or P04) was added, and a part was added with colloidal silica (S).

 3. Chromate treatment method

 After applying the resin chromate treatment solution to the metal plate using a roll coater, the metal plate is dried at various temperatures and speeds (drying time) of the maximum reach of the metal plate, and the surface of the resin particles and the bulk In the above, resin chromatized metal plates having different fusion states were obtained. The following analyzes and performance evaluations were performed on these samples.

4. Structural analysis of resin-coated π-coated film

 (1) Measurement of average film thickness H

 The cross section of the resin chromate-treated metal plate was observed using TEM and SEM, and the average film thickness was measured.

 (2) Measurement of P and Ra values

 Using an atomic force microscope (TM-AFM) in tapping mode, scan the five-corner area of the resin chromate treated surface, and find the distance between Ra and any straight line with a total length of 20 βm in this area. P obtained in the above was measured respectively.

 (3) Sectional structure analysis

Using an ultramicrotome, cut the treated metal plate horizontally at the desired position on any 10 places of the same resin chromate-treated metal plate to obtain ultra-thin sections. I made each one. These images were taken at a magnification of 50,000 by transmission electron microscopy ^^. From the area of 1.2 / 2mxl.2 / zm, the area ratio of the resin phase and the area of the fused resin particles in the resin phase The rate was measured and the average value of 10 points was calculated.

 5. Performance evaluation of resin chromate treated metal plate

 (1) Chromium residual rate

 The amount of chromium in the ¾ before and after the Arikari degreasing test was measured using fluorescent X-rays, and the Kumomu residual ratio was calculated by the following formula in terms of metal Kumomu.

(Amount of chromium in the film after Al-rikari degreasing test)

Chromium residual rate (%) = X 100

 (Amount of chromium in the film before Al-Kari degreasing test)

 In the alkali degreasing test, the process of spraying the alkali degreasing solution on the test material at room temperature for 3 minutes and then washing with water for 1 minute was repeated 5 times.

 (2) Corrosion resistance of processed part

 After subjecting the test material to Erichsen processing to a height of 7 mm, a salt spray test was performed for 72 hours, and the degree of 鐯 generation in the processed part was evaluated. ◎: No occurrence

 〇: White 鐯 Less than 5%

 △: White △ 5% or more and less than 15%

 X: White 超 Over 15%

 (3) Corrosion resistance of damaged area

 After a cross cut was made in the test material to reach the base, a salt spray test was performed for 72 hours to evaluate the degree of 锖 generation at the damaged part.

 ◎: No occurrence

 〇: White 锖 Less than 5%

Δ: White 锖 5% or more and less than 15% x: White 超 More than 15%

 As can be seen from Table 1, in the present invention example in which the ratio Ra ZP of the convex part average spacing P to the center plane average roughness Ra is 0.3 or less, the chromium residual ratio is about 80% or more, and the processed part Excellent corrosion resistance at the damaged part. Further, when the ratio P / H of the average thickness H of P to the resin chromate is in the range of 0.01 to 0.5, more excellent performance is exhibited. On the other hand, in the comparative example where Ra / P is more than 0.3, the chromium residual ratio is less than 80%, and the corrosion resistance of the worked part and the scratched part is inferior.

 Further, as can be seen from Table 2, the cross-sectional structure is within the scope of the present invention, that is, the area ratio of the resin phase in an arbitrary cross section of the resin chromate film is 40 to 95%, and the resin is fused to the resin. In the examples of the present invention, in which the body has a ^^ ratio of 20 to 100%, the residual chromium ratio is 95% ±, and the corrosion resistance of the worked portion and the scratched portion is further improved.

 In Tables 1 and 2, A1 is RaZP≤3 and A2 is

P / H = 0.01 to 0,5 and B indicate the area ratio of the resin phase of 40 to 95% and the area ratio of the resin fusion product of 20 to 100%, respectively.

Table 2

麵 Example 2

 1. Types of metal plate

EG: Electric zinc plated steel plate (20 g / m ² with plating)

 2. Resin chromate treatment bath

 (1) Types of chromic acid

 Chromic anhydride partially reduced by starch was used.

 (2) Type of resin

 The following four acryl-based soap-free emulsions were used.

 A: A copolymer of isopropyl acrylate and methyl methacrylate.

 B: sec—A copolymer of butyl acrylate and methyl methacrylate.

 C: sec-butyl acrylate, 2-ethynolehexyl acrylate, and methyl methacrylate are copolymerized.

 D: Tert-butyl acrylate, sec-butyl acrylate, and methyl methacrylate are copolymerized.

 (3) Other additives

 Phosphoric acid and colloidal silicide were also added.

 3. Chromate treatment method

After applying the resin chromate treatment liquid to the metal plate using a single mouthpiece, the maximum plate temperature of the metal plate, the inside of the furnace, the wind speed, and the drying time were changed as shown in Table 3. . The chromium deposition amount was 6 Omg m ² .

 4. Structural analysis of resin chromate film

 Performed in the same manner as in Example 1.

5. Performance evaluation of resin chromate treated metal plate (1) Chromium residual rate

 ^ Measured as in Example 1.

 (2) Processability

 The sample subjected to the Erichsen processing with a height of 7 mm was subjected to a salt spray test, and the white area generation rate in the processed portion after 100 hours was evaluated.

 ◎: White 鐯 Less than 5%

 〇: White 锖 5% or more, less than 10%

 Δ: White 鑌 10%, less than 30%

 X: White 鑌 30% or more

 (3) Flat plate corrosion resistance

 The flat plate sample was subjected to a salt spray test to evaluate a whitening area ratio after 240 hours.

 ◎: White 锖 Less than 1%

 〇: White 锖 1% or more, less than 5%

 △: White △ 5% or more, less than 10%

 X: White 鐯 10% or more

 Table 3 shows the results of the performance evaluation test. As can be seen from Table 3, even with chromate films from the same resin and treatment bath, the film structure and the performance differ greatly depending on the drying conditions. Therefore, in order to obtain the product of the present invention, it is necessary to select not only the existing resin and chromate bath but also the drying conditions suitable for each resin and bath.

In Table 3, A1: Ra / P≤3, A2: PZH-0.01 to 0.5, B: Area ratio of resin phase 40 to 95%, and area ratio of resin fused body 20 to 100% , And. Table 3

Example 3

GI: soluble lead-plated steel sheet (plating with 90g / m ²⁾

EG: Electroplated steel sheet (plated «20g / m ² )

Zn-A 1: soluble lead one aluminum-plated steel sheet (with plating «S120 g / m ^2, the plating composition A lZZn = 5/95)

GA _: Alloyed hot-dip galvanized steel sheet (coating weight 45 g / m ² , plating composition F e / Zn = l 5/85)

AL: Steel plate with molten aluminum (plated «100 g / m ² )

 2. Types of chromic acid

A product obtained by partially reducing chromic anhydride was used. The concentration of chromic acid was 20 to 50 g / 1 in C R_〇 ₃ basis.

 3. Types of resin emulsion

The following resin emulsion was used. Bath of the resin Emarujiyon was 3-7 times the chromium San體(Cr_〇 ₃ equivalent) in terms of solid content. Water-soluble polyacrylic acid (symbol X) was used as a comparative example.

 A: An acryl-epoxy emulsion prepared by copolymerizing propyl acrylate, butyl acrylate, methacrylic acid, and glycidyl methacrylate without using a low molecular weight surfactant.

 B: Acryl emulsion prepared by copolymerizing methyl methacrylate, butyl acrylate, and methacrylic acid without using a low molecular weight surfactant

C: acryl-based emulsion obtained by copolymerizing methyl methacrylate, butyl acrylate, methacryloleic acid, and hydroxy acrylate without using a low molecular weight surfactant D: Aromatic vinyl emulsion copolymerized with vinylphenol, styrene and methacrylic acid

 E: Olefin copolymerized with butadiene, acrylic acid, and hexyl acrylate

—Acrylic emulsion

 F: Aromatic vinyl emulsion prepared by emulsion polymerization of methacrylic acid and styrene in the presence of iSi ^ surfactant

 X: Water-soluble polyacrylic acid

 4. Other additives

 Phosphoric acid (P) was added, and colloidal silica (S) was added to some of them. The added amount of phosphoric acid was 1.5 times or more the chromic acid concentration, and the added amount of colloidal silica (in terms of Si0 ゥ) was 0.5 to 1.5 times the chromic acid MJ ^.

 5. Chromate treatment method

 The coating was performed using a roll coater.

 6. Control of area ratio and distribution density of chrome pool

By controlling the particle size of resin emulsion particles, the type and concentration of functional groups, the temperature history of the chromate treatment bath and the phosphorus in the treatment bath M :, the drying rate after coating; Samples were prepared by dispersing the scum in the coating at various area ratios and distribution densities. As an example, Sample No. 46 of the present invention in Table 4 will be described in detail. The resin particle size is about 150 nm, the functional groups are carboxyl group (concentration: 1 O% as methacrylic acid) and hydroxyl group a: 5% as hydroxyethyl acrylate, and chromic acid (concentration 3 Two times as much as 0 g of 1) phosphoric acid and five times as much resin emulsion were added, and after the bath was allowed to stand at room temperature for one week, it was applied. The drying plate temperature was 60 ° C and the heating rate was 2 ° C / sec. 7. Measurement of area ratio and distribution density of chrome pool

 Using an ultramicrotome, a section of the resin chromate film formed by cutting the coated and dried chromate-treated metal plate horizontally at the normal temperature to the treated surface at room temperature, using a transmission electron microscope and a magnification of 20000 × Photographs were taken of 10 visual fields with an area of 5 ^ mx5 / m or more, and the area ratio and distribution density of the chromium pool were measured, and the average value was obtained. As a result of the surface measurement by AFM, the RaZP value of all the test materials was 0.3 or less.

 8. Performance evaluation method

 (1) Chromium residual rate

 The measurement was performed in the same manner as in Example 1.

 Chromium residual rate 95% or more

 〇: Chromium residual rate 90% or more and less than 95%

 △: Chromium residual rate 80% or more and less than 90%

 X: Chromium residual rate less than 80%

 (2) Processing food

 After subjecting the test material to Erichsen processing to a height of 7 mm, a salt spray test was performed, and the white spot generation area ratio in the processed part was actually measured. The test period was 6 days (144 hours) for GI, EG, and Zn-AS, and 9 days (216 hours) for AL force.

 ◎: White 锖 Occurrence rate less than 5%

 〇: Whitening rate 5% or more and less than 10%

 Δ: Whiteness rate 10% or more and less than 20%

 X: White 鐯 incidence rate 20% or more

 (3) Paint adhesion

The sample was coated with melamine alkyd paint at 20 μπι, dried, and immersed in boiling water for 30 minutes. Immediately on the grid test (1mm grid 10X10, tape peeling) The peeling area ratio of the coating film was examined.

 ◎: Peeling rate less than 5%

 〇: Peeling rate 5% or more and less than 10%

 △: Peeling rate 10% Ri: less than 20%

 X: Peeling rate 20% or more

 Table 4 shows the performance evaluation results. As can be seen from Table 4, the area ratio of the resin phase is 40 to 95%, the area ratio of the fused resin is 20 to 100%, and the area ratio of the chromium pool is 5 to 60%. The invention of the present invention, in which the distribution concentration of the chromium pool is 10 or more, shows more excellent corrosion resistance in the processed portion and paint adhesion, and has a high chromium retention rate.

 On the other hand, the area ratio of the chromium accumulation and the distribution concentration power The comparative examples of the sample numbers 49, 50, 54, 56, 57, 61, 62, 66, 67, 71 and 75 which are out of the scope of the present invention are as follows. Inferior in processing and corrosion or paint adhesion.

In Table 4, B: Area ratio of resin phase is 40 to 95%, and area ratio of resin fusion body is 20 to 100%, C1 _: Chromium accumulation area ratio is 5 to 60%, C2: Chromium accumulation distribution The concentration is 10 or more.

Table 4

Table 4 (continued)

 Configuration of treatment of control factors Cross-sectional structure of treated film Performance of treated plate

 Correspondence to numerical limitation Sample Sample Resin phase

 In the thickness Chromium Chromium Y: Within the range No. Resin Resin CrH Resin Resin Residue Pool Cr Processed part Paint N: Metal plate outside the range Adhered amount Additive area ratio Particle fusion area ratio distribution Remaining Rate Corrosion resistance Adhesion

 麵 (ffm) (mg / nf) (iim) (¾) Landing surface (X) Density

 Rate B C 1 C 2

(¾)

 63 C GA 0.150 60 P, s 0.6.60 60 42 33 〇 〇 〇 Y Y Y

Λ GA 0. 100 60 P, s 0.5 60 25 19 11 〇 Δ 〇 Y Y Y

65 B GA 0.150 60 PCM 0.5 to 5 65 21 30 〇 〇 〇 Ϊ Y Y

66 B GA 0.150 60 PCM 0.5 30 68 61 26 Δ ◎ X N N Y

67 X GA 1 60 P, s 0.1 ― 1 0 〇 X 〇 N N

68 A Ζη-ΛΙ 0.150 60 P, s 0.6 75 80 8 13 〇 Δ 〇 Y Y Y

69 B Zn-AI 0.150 60 P, s 0.6.64 60 1Ϊ 18 〇 〇 Y Y Y Y

TO C Zn-Ai 0.150 60 P, s 0.6.50 50 44 33 〇 〇 〇 Y Y Y

? 1 X Ζη-ΛΙ 60 P, s 0.2 0 0 〇 X 〇 N N

72 A AL 0.150 60 P, s 0.6 80 50 10 15 〇 Δ 〇 Y Y Y

73 B AL 0.150 60 P, s 0.6.68 68 22 24 〇 〇 〇 Y Y Y

U C AL 0.150 60 P, s 0.6 Π 75 39 27 〇 〇 〇 Y Y Y

? 5 X AL 60 P, s 0.20 0 〇 X 〇 NN

Sickle example 4

 1. Types of metal plate

 The following metal plates were used for the resin chromate treatment.

GI: Hot-dip galvanized steel sheet (plated «S90 gZm ² )

EG: Electro-galvanized steel plate (coating weight 20 g / m ² )

Z nA 1: hot dip one aluminum-plated steel sheet (coating weight 120 g / m ^2, the plating composition Α 1ΖΖη = 5/95)

 2. Resin chromate treatment bath

 (1) Types of chromic acid

 A product obtained by partially reducing coumic anhydride with starch was used.

 (2) Types of water-dispersible emulsion resin

 An acryl-based soap-free emulsion resin having the following composition was used.

 Notation example: In the case of MMAZBAZMAA (45/45/10), a copolymer of 45% by weight of MAA, 45% by weight of BA, and 10% by weight of MAA. However, MMA… Methyl meta acrylate. B A… Putyl atarilate. MMA: Methyl acrylic acid. St… Styrene. HEMA… Hydroxyethyl methacrylate. GMA: Glycidyl methacrylate. BD ... butadiene.

 A1: MMA / BA / MAA (4-5 / 45/10)

 A2: MMA / BA / MAA (40/40/20)

 A3: MMA / BA / MAA (35/35/30)

 B 1: St / BA / MAA (45/45/10)

 B2: S ΐ / ΒΑ / χΜΑΑ (40/40/20)

 Β 3: St / BA / MAA (35/35/30)

 C1: MMA / BA / HEMA (47/47/6)

C2: MMA / BA / HEMA (44/44/12) C3: MMA / BA / HEMA (38/38/24)

 D1: MMA / B A / GMA (40/40/20)

 D2: MMA / BA / GMA (35/35/30)

 D3: MMA / BA / GMA (30/30/40)

 El: MMA / BA / BD / MAA (30/30/30/10)

 E2: MMA / BA / BD / MAA (26/26/26/22)

 E3: MMA / BA / BD / MAA (23/23/23/31)

 (3) Other additives

 Phosphoric acid (P) was added, and colloidal silica (S) was added to some of them.

3. Processing method

 Coating was carried out using a roll coater and dried until the film reached 11 ° C to obtain a resin chromate-treated metal plate.

 4. Performance evaluation method

 (1) Surface structure evaluation

 Using an atomic force microscope (TM-AFM) in tapping mode, any 10 locations on the resin chromate-treated surface are scanned within a 1-zm range, and a 50-nm high-pass filter is applied by Fourier transform in each range. One processed image was obtained. In each image, the area ratio of the convex portion having a displacement of 0.5 nm or more was actually measured, and the average value of 10 locations was obtained. The value of Ra no P was 0.3 or less for all the test materials.o

 (2) Chromium residual rate

 Measured in the same way as ι. (3) Corrosion resistance of processed part

 After subjecting the test material to Erichsen processing to a height of 7 mm, a salt spray test was performed for 72 hours to evaluate the degree of 鐯 generation in the processed part.

◎: No occurrence 〇: White 锖 Less than 5%

 △: White △ 5mJil Less than 5%

 X: White 超 Over 15%

 (4) Eating damage

 After inserting a slotted cut reaching the base material into the test material, a salt spray test was performed for 72 hours to evaluate the occurrence of 鐯 at the damaged part.

 ◎: No occurrence

 〇: White 锖 Less than 5%

 Δ: White 锖 5% or more and less than 15%

 X: White 超 Over 15%

Table 5 shows the evaluation test results. In the comparative example, the residual chromium ratio was 80% or less, and white spots were observed in the processed portion and the scratched portion. On the other hand, in the example of the present invention, the chromium residual ratio was 95% Η ±, and no whitening was observed in the processed portion and the scratched portion.

Table 5

 Composition of treatment Performance of treated plate Cr Addition of resin Cr-processed part in converted image Scratched part Example Type Addition Convex part of 0.5ηπι or more Residual rate Corrosion resistance Area ratio of corrosion resistant agent (%) (%)

 丄 A 丄 o

 s 50 P 5 99 ◎ ◎

 A 50 P 12 95 ◎ ◎ o 50 P, s 15 98 ◎ ◎

4 丄 50 P 10 98 ◎ ◎

5 Zn—Al A 2 50 P 13 97 ◎

0 E GB 1 50 p 1 97 ◎ ◎

7 E GB 2 50 p 12 95 ◎ ◎

8 E G C 1 50 p 2 99 ◎ ◎ Light

9 E G C 2 50 p 10 99 ◎

10 E G D 1 50 P 8 99 ◎ ◎ Example

11 E G D 2 50 P 15 98 ◎ ◎

12 E G E 1 50 P 4 98 ◎ ◎

13 E G E 2 50 P 1S 95 ◎ ◎

14 E G A 3 50p 28 72 0 ο

15 E G A 3 50 P, s 35 78 o ο

 ratio

16 G I A 3 10 P 31 75 X X

 17 Zn-Al A3 50 P 29 73 Δ Δ

 Comparison

18 EG B 3 50 P 32 66 X ◎ 9 EG C 3 50 P 26 78 〇 〇

Example 0 EG D3 50 P 26 62 X 〇 1 EG E 3 50 P 33 69 XX Example 5

 1. Types of metal plate

 The following three types of metal plates were used for chromate treatment.

GI: Hot-dipped steel plate with lead plating (coating weight 90 gZm ² )

EG _: Electro-galvanized steel sheet (coating weight 20 g / m ² )

Zn-A 1: hot-dip zinc-aluminized steel sheet (plated »* 120 g / m ² , plating composition A i / Zn = 5/95)

 2. Resin chromate treatment bath

 (1) Types of chromic acid

A product obtained by partially reducing coumic anhydride with starch was used. The concentration of chromic acid and 30gZl at C r 0 ₃ in terms of the concentration of six of chromium was 19 g / 1.

(2) Types of resin and carbonyl compound

 Acrylic soap-free emulsion resin was used. That is, an acrylic resin was used as the resin, and a carboxyl group was used as the carbonyl compound. The concentration of the emulsion in the bath was 100 gZ1 in terms of solid content.

 (3) Other additives

 Phosphoric acid (P) was added, and colloidal silica (S) was added in some cases. The addition amount of phosphoric acid was 60 g Z1 in terms of pure content, and the addition amount of colloidal silicide force was 50 gZl in terms of SiO 2.

 3. Chromate treatment method

 Coating treatment was performed using a roll co. The thickness of the resin chromate film was 0.5 m.

4. Controlling the strength of the chelating bond between the chromium ion and the carbonyl compound in the resin The ratio of chromic acid to sulfuric acid in the treatment bath depends on the ratio of the concentration of the carbonyl compound in the resin to the concentration of chromic acid, and the heat of the treatment bath. History, heating power in the drying process after coating By controlling the processing time and temperature of post-treatment (boiling water, hot water immersion treatment) after turning and drying, the strength of the chelating bond between the carbonyl compound in the resin and chromium and the chelation reaction A sample was prepared in which the degree of progress was varied.

 5. Measurement and quantitative analysis of infrared absorption spectrum

 After the prepared sample was immersed in boiling water for 30 minutes, the infrared absorption spectrum of the chromate treated surface was measured by the high sensitivity reflection method. In the calculation of the relative intensity of the peak, the background as indicated by «in FIG. 10 was assumed, and the relative intensity was determined using the height from this to the peak. In addition, as a result of surface measurement by AFM, the value of Ra / P was 0.3 or less for all the test materials.

 6. Performance evaluation method

 (1) Chromium residual rate

 The measurement was performed in the same manner as in Example 1.

 (2) Processability

 After subjecting the test material to Erichsen processing to a height of 7 mm, a salt spray test was conducted for 72 hours to evaluate the degree of 锖 generation in the processed part.

 ◎: No occurrence

 〇: White 锖 Less than 5%

 Δ: White 鲭 5% or more and less than 15%

 X: White 超 More than 15%

 (3) Corrosion resistance of wound

 After applying an epoxy-based electrodeposition coating of 20 microns and a polyurethane-based static coating of 40 micron to the test material, inserting a cross cut that reaches the painted surface, and then subjecting it to outdoor exposure at the coastal area for one hour Then, the width of occurrence of prestar in the coating film from the cross-cut portion was measured.

◎: Blister width less than 1 mm 〇: Bliss evening width 1 mm or more and less than 5 mm

 Δ: Prestar width 5mm i: l Less than Omm

 X: Prister width more than 10 mm

 (4) Paint adhesion

 The test material is coated with a melamine alkyd paint of 20 microns, dried under the specified conditions, immersed in warm water of 50 ° C for 1 hour, then put a lmm grid on the painted surface with a cutter knife and peeled off with cellophane tape We checked the number of go boards.

 ：: No peeling

 〇: Peeling rate less than 10%

 △: Peeling rate 10% or more and less than 30%

 X: Peeling rate more than 30%

Table 6 shows the results of the performance evaluation test. As can be seen from Table 6, the Example of the present invention has a higher chromium residual ratio, and is excellent in the corrosion resistance of the processed portion, the corrosion resistance of the scratched portion, and the paint adhesion, as compared with the Comparative Example.

Table 6

 Composition of processing Infrared absorption peak Performance of processing plate

Material High wave number peak Low wave number peak Example No.Metal plate Other Cr processing part Scratch paint

No. Type Additive Position Relative strength Position Relative strength Fixed rate Corrosion resistance Corrosion resistance Adhesion

(cnr ¹ ) (cm- ¹ ) (¾)

 1 U 1 50 ― ― ― ― β o U

2 50 1? 09 100 ― 1 03;

 〃

3 π τ 50 p ― ― 156? 100 Q Q 888

4 50 p 1730 100 〃

5 G I 50 p Π30 100 1595 5 (Θ) (Θ) (Q) Example of the present invention

6 G I 50 p 1130 100 1595 10 85 〃

7 G I 50 P 1 ~ 30 100 1595 20 90 ◎ ◎ ◎ 〃

8 G I 50 P 1730 100 1595 50 95 ◎ ◎ 〇

 9 G I 50 P Π30 100 1595 110 99 ο 〇 Δ 〃

10 G I 50 P 1730 100 1490 30 98 △ X 比較 Comparative example

11 G I 50 P 1T30 100 1500 30 85 ◎ 〇 例 Example of the present invention

12 G I 50 P, s 1T30 100 1660 30 Ϊ5 ◎ ◎ 〇 〃

13 G I 50 P, s 1730 100 1680 30 65 ◎ ◎ 〇 Comparative example

\ E G 50 P, s 1 Ϊ15 100 1565 20 80 ◎ ◎ 例 Example of the present invention

15 ZN-AL 50 P, s 1715 100 1500 20 75 ◎ 〇 〇

Table 6 (continued)

 Composition of processing Infrared absorption peak Performance of processing plate

 51

Charge High wave number peak Low wave number peak Example

No.Metal plate Other Cr processing part Scratch paint

 ^ Type Additive Position Relative Strength Position Relative Strength Fixed Rate Corrosion Resistance Corrosion Resistance Adhesion

 (cm- ') (¾) («) (¾)

 16 EG 60 P, s 1727 100 159? 15 85 Δ Δ 例 Example of the present invention

 17 EG 60 P, s 1Ϊ2Τ 100 1598 17 88 Δ Δ ◎ 〃

 18 EG 60 P, s Π28 100 1597 21 91 〇 〇

 19 EG 60 P, s 1730 100 1597 23 95 〇 〇 ◎ 〃

 I

 20 EG 60 P, s Π29 100 159? 28 98 〇 ◎ ◎ 〃

21 EG 60 P, s 1729 100 1595 29 99 ◎ ◎ ◎

Example 6 Three types of aluminum composite plates shown in Table 7 below were used as metal plates to be subjected to chromate treatment. Table 7 (wt%) material Cu Mg S i Zn Mn Fe Cr T i Al

AL1 0.5-0. 9 0.5-1.0.0 0.7-1.1 0.15 15.15-! 1.45 0.0 0.10 0.10 Remaining

AL2 2.2 to 3.0 0 0.3 to 0.6 0.6 0.5 0.25 0.10 to 0.40 0.50 0.10

AL3 0.15 4.! ) To 5.0 0.20 0.25 0.

2. Resin chromate treatment bath

 (1) Chromic acid

A product obtained by partially reducing chromic anhydride with starch was used. The concentration of chromic acid and 3 0 g / l in C R_〇 ₃ basis, the concentration of six of chromium was 1 9 gZ l.

(2) Types of resin and carbo-niiru dani

 Acrylic soap-free emulsion resin was used. That is, an acrylic resin was used as the resin, and a carboxyl group was used as the carbonyl compound. The concentration of the emulsion in the bath was 1001 in terms of solid content.

 (3) Other additives

Phosphoric acid (P) was added, and colloidal silica (S) was added in some cases. The addition amount of phosphoric acid is set to 6 0 g / 1 in pure content terms, the added amount of colloidal silica was 5 0 gZ l with S i 0 ₂ conversion.

 3. Chromate treatment method

 The coating treatment was performed using a mouth coater. The thickness of the resin chromate film was 0.5 m.

 4. Control of the strength of the chelating bond between the chromium ion and the carbonyl compound in the resin Concentration of hexavalent chromium in the treatment bath and the concentration of sulfuric acid and fluoride ions, which are inorganic additives, By changing the bath temperature and time during stirring, and the water temperature and treatment time in the immersion treatment after coating and drying, the strength of the chelate bond between the carbonyl compound and chromium in the resin and the chelate reaction Samples with varying degrees of progress were made. The following analyzes and performance evaluations were performed on these samples.

5. Infrared spectrum and measurement and quantitative analysis

 Performed in the same manner as in Example 5.

 6. Performance evaluation method

Performed as in Difficult Example 5. However, in the corrosion test of the power section, salt spray was performed for 144 hours. Thereafter, the white area ratio was measured. In addition, the stability of the aqueous solution of the chromic acid compound after stirring with the coexisting ions was evaluated according to the following criteria.

 ◎: Stable for more than 2 months when left at room temperature

 〇: If left at room temperature, it sinks in more than 1 month and less than 2 months ^^

 △: When left at room temperature, it sinks in 7 days or more and less than 1 month

 X: Sink in less than 7 days if left at room temperature ^^

Table 8 shows the results of the performance evaluation test. As can be seen from Table 8, all of the examples of the present invention have a higher chromium residual ratio than the comparative examples, and are excellent in the corrosion resistance of the processed portion, the corrosion resistance of the scratched portion, and the paint adhesion.

Table 8

 Heating and stirring with coexisting ions Water immersion treatment Infrared absorption peak treatment plate performance

 Money

 Sulfuric acid bath temperature Stirring low temperature 7K Wavenumber peak Low wavenumber peak Example

岙 m Time temperature Temperature time Cr Cracked part 麵

 Property Position Relative strength Position Shin Relative strength Fixed rate Resistance: 1¾ Corrosion resistance Adhesion

(%) (%) (ΐ) (time) (t) ½}) (cm— (¾) (cm— ¹ ) (¾) (¾)

 1 AL1 o 1 40 24 〇 100 30 100 55 ◎ ◎ Δ

 2 AL1 0.1 1 40 24 〇 100 30 t 7Q () l u υ 1 n υ 85 ◎ ◎ ◎ Example of the present invention n

 3 AL1 1 40 o 100 30 1 1 πη 1 ςος

 171 o U en 90 ◎ ◎

 4 ALI 1 40 2 o 100 30 171fl u u I jy j 3 U 99 Δ Δ Δ

 5 All o 40 24 X 100 30 1 i) U 11 Π uΠ u 1 t; qi;

 l ϋ 0 U 88 ◎ © o Comparative example

_{

 6 ALI 0.140 24 Δ100 30 11 o u 1 on ¾n iy 88 ◎ ◎ ◎ Example of the present invention

J

 7 All 40 24 ◎ 100 30 Π30 100 1595 30 89 ◎ ◎ ◎

8 ALI ₁ ! 30 24 〇 100 30 Π 30 100 1595 1 60 ◎ ◎ 〇

9 ALI 40 10 〇 100 30 1730 100 1595 5 67 ◎ ◎ 〇

10 ALI 40 24 〇 100 30 l? 3fl 100 1595 30 89 ◎ ◎ Example of the present invention

11 ALI 40 24 〇 50 30 1730 100 1595 10 85 ◎ ◎ ◎

 12 All 40 24 〇 20 30 1730 100 1595 5 75 ◎ ◎ 例 Example of the present invention

13 ALI 40 U 〇 100 0.1 Π 30 100 1595 10 85 ◎ ◎ 〇

14 M2 40 U 〇 100 30 1730 100 1595 30 89 ◎ ◎ 〇

15 AL3 40 2 〇 100 30 1T30 100 1500 30 88 ◎ ◎ 〇

Difficult case 7

 1. Types of metal plate

 The following three types of metal plates were used for chromate treatment.

GI _: Hot-dip galvanized steel sheet (plated «90 gZm ² )

EG ： Electric m¾ Lead-plated steel plate (plated «20gZm ² )

ZuA1: Hot-dip zinc-aluminized steel sheet (2 鋼板 / m ² with plating)

 (Plating composition A l / Zn = 5/95)

 2. Resin chromate treatment bath

 (1) Types of chromic acid

A product obtained by partially reducing chromic anhydride with starch was used. Of chromic acid ^ was 30g / l (Cr0 ₃ conversion).

 (2) Resin emulsion

 An emulsion prepared by copolymerizing propyl acrylate, butyl acrylate, styrene, and hydroxyshethyl methacrylate was used. The concentration of the emulsion in the bath was 100 gZl in terms of solid content.

 (3) Other additives

Phosphoric acid, fluoride ions and colloidal silica were added. The addition amount of the colloidal silica was 50 g / l in S I_〇 ₂ equivalent. The concentrations of the phosphoric acid and the fluoride ions were appropriately determined in order to control the amount of the chromic acid conjugate dispersed in the resin emulsion particles.

3. Chromate treatment method

 The coating treatment was performed using a mouth coater. The chromium deposition amount was 2 OmgZm.

 4. Control of average area ratio and average density of chromic acid conjugate compound dispersed in resin emulsion particles

Type and concentration of functional groups in resin emulsion particles, temperature of chromate treatment bath and By controlling the amount of phosphoric acid and fluoride in the treatment bath, the drying after coating; and the heating butter in the process of ^ X, the average ratio and density of the chromic acid compound dispersed in the resin emulsion particles can be reduced. A modified sample was made.

 5. Measurement of average area ratio and average density of dispersed chromium oxide ^ [

 Using an ultramicrotome, the chromate-treated metal plate after coating and drying was kept at room temperature, and the section of the resin chromate film formed by cutting the treated surface in the horizontal direction was observed with a transmission electron microscope. For the resin emulsion particles, the area ratio and density of the chromic acid compound dispersed in the flutter particles were actually measured, and the average value was determined.

 6. Performance evaluation method

 (1) Chromium elution rate

 Spraying the test piece with Alkyri degreasing solution at room temperature for 3 minutes, followed by washing with water for 1 minute After the process of repeating the process 5 times, the ratio of the lipstick before and after was determined by X-ray fluorescence analysis. It is determined that the chromium elution rate is preferably 20% or less.

 (2) Processing food

 After the supplied W was subjected to Erichsen processing to a height of 7 mm, a salt spray test was carried out for 72 hours, and the white area generation area ratio in the processed portion was actually measured. It was determined that the area ratio of white spots was good when it was 40% or less.

 Fig. 11 shows the ratio of the dispersed chromic acid compound and the whiteness of the processed part when the emulsion particle diameter is 100 nm: L 70 nm, and the dispersion density of the chromic acid compound in the resin particles is 20 to 30 particles per 10 Onmxl 0 Onm. The relationship with the incidence was shown. FIG. 12 shows the relationship between the area ratio of the dispersed chromic acid conjugate and the chromium elution rate. As a metal plate

EG and GI were used. In the figure, the black circles indicate that the chromic acid compound was dispersed in the resin particles when the hexavalent chromium concentration in the treatment bath was 50%, and that the processing was audible, and the area ratio was 5% JLt. It has a clear effect. Processing when the area ratio exceeds 80% This is because the cracking of the resin chromate film due to processing becomes prominent. The effect of the area ratio on the chromium elution rate is small. The open circles represent the case where the hexavalent chromium ′ is 70% and the oxalic acid compound is dispersed in the resin particles. The erosion rate of the chromium is high, although the processing corrosion is good.

 Fig. 13 shows that the dispersion density of the chromic acid compound was processed when the particle size of the emulsion was 100 to 170 nm and the average area ratio of the chromic acid compound dispersed in the resin particles was 30 to 40%. This is the result of examining the effect on the partial corrosion resistance over time of the salt spray test. Zu—A1 was used as the metal plate. When the dispersion density is low, that is, the number of spotted kumic acid compounds is small and the size of the spots is large, the salt water is sprayed for a longer time and the dispersion density is higher than that of the higher one. It can be seen that the corrosion resistance of the processed part was significantly deteriorated.

Claims

The scope of the claims

1. On a metal plate on which a resin chromate film containing τ 樹脂 dispersible emulsion resin and a chromium compound as main components is formed, the average distance between the protrusions obtained by measuring the outermost surface of the resin chromate film using an atomic force microscope A chromium-insoluble resin-chromate-treated metal plate, wherein the ratio R a ZP of Ρ to the center plane average roughness Ra is 0.3 or less.

 2. The ratio PZH between the average interval P of the protrusions and the average thickness H of the resin chromate is

2. The chromium-insoluble resin-chromate-treated metal plate according to claim 1, wherein the thickness is from 0.01 to 0.5.

 3. In an arbitrary cross section of the resin chromate film, the area ratio of the resin phase separated by the chromium compound and a clear boundary is 40 to 95%, and the area ratio of the resin fusion material in the resin phase is The chromium-insoluble resin-chromate-treated metal plate according to claim 2, wherein the content is 20 to 100%.

 4. Emulsion particles are missing on any cut surface when cut horizontally with respect to the resin chromate film surface, and the chromium containing chromium compound has an area ratio of 5 to 60% by area. 4. The insoluble resin chromate-treated metal plate according to claim 3.

5. The distribution concentration of the chrome pool is

The chromium-insoluble resin-chromate-treated metal plate according to claim 4, wherein the number is 10 or more.

 6. In the image obtained by subjecting the surface unevenness distribution of the resin chromate to high-pass filter processing at a wavelength of 50 nm by two-dimensional Fourier transform, the area ratio of the convex portion showing a displacement of 0.5 nm or more is 20% 2. The metal plate of claim 1, wherein the metal plate is treated with a hardly soluble resin chromate.

7. Infrared absorption analysis after the resin chromate film is immersed in boiling water shows that the resin chromate film is within the range of 1670 to 1760 cm- ¹ and 1500 to 1660 cm- ^1. 1 or less each 2. The metal plate of claim 1, wherein the metal plate has a low infrared absorption peak.

8. The intensity ratio of the maximum infrared absorption peak within the range of 1670 to 1760 cm- ^{1 and} the range of 1500 to 1660 cm- ¹ by the absorbance is as follows: high wavelength region peak: low wavelength region peak = 1: 0.1 to 8. The chromate-resistant resin-chromate-treated metal plate according to claim 7, wherein the ratio is 1: 1.

 9, the chromium compound is dispersed in the form of spots on the surface of the emulsion resin particles and inside the Z or emulsion resin particles, and the area ratio of the chromium compound dispersed in the spots to the emulsion resin particles is arbitrary cutting of the emulsion particles. 2. The hardly soluble resin chromate-treated metal plate according to claim 1, wherein the average value of the surface is 5 to 80%.

 10. The hardly soluble chromium resin according to claim 9, wherein the dispersion density of the chromium compound dispersed in a! ^ Shape at an arbitrary cut surface of the emulsion resin particles is 20 per 10 Onmxl 0 Onm. Chromated metal plate.